Python 3 preparation: make fallback SysCallError an actual exception class. The code defines a fallback version of SysCallError when import of OpenSSL.SSL. But in Python 3, defining it as None and then using in "except" statements results in: TypeError: catching classes that do not inherit from BaseException is not allowed

def init_severity(db, cl, nodeid, newvalues):
    """Make sure severity is set on new issues"""
    if 'severity' in newvalues and newvalues['severity']:
        return

    normal = db.severity.lookup('normal')
    newvalues['severity'] = normal

def init(db):
    db.issue.audit('create', init_severity)